1. Field of the invention
The present invention relates to an electronic control apparatus for an automotive automatic power transmission.
2. Description of the Background Art
In the case of an electronically controlled automatic power transmission of an automotive vehicle, an electronic control unit is installed in the vehicle apart from a main frame of tile automatic power transmission.
Although the electronic control unit (or device) can be installed inside of the main frame of the automatic power transmission (hereinafter simply referred to as A/T) for example, as disclosed in Japanese Patent Application First Publications Heisei 1-312252 (published on Dec. 18, 1989) Heisei 2-3740 (publised on Jan. 9, 1990), and Heisei 2-3744 (published on Jan. 9, 1990), it is generally installed in a vehicle compartment of the vehicle with its thermal resistance characteristic, vibration-proof characteristic, and dust-proof characteristic taken into consideration.
Then, usually, the main frame of the A/T and electronic control device are manufactured at different places and are integrated during an assembly of the A/T in the vehicle.
Hence, the randomly selected main frame and randomly selected electronic control device are mutually integrated with each other. Accordingly, if gear ratio shift lines are slightly deviated due to some variation (or deviation) in an output characteristic (variation in output value of hydraulic (oil pressure) with respect to a duty ratio) of a solenoid used for a control of the speed gear shift, it may not be possible to correct the variations described above by means of the electronic control device.